uboot-envtools: add more kirkwood boards

- SheevaPlug
- SheevaPlug with eSATA
- GuruplugServerPlus

Signed-off-by: Gerald Kerma <dreagle@doukki.net>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@43747 3c298f89-4303-0410-b956-a3cf2f4a3e73